The invention relates to a remote viewing apparatus having a miniature camera and an adjustable lens. In particular, the invention relates to remotely controllable means for directionally supporting and optically adjusting the camera and lens for remote viewing.
In certain applications, particularly in connection with the repair and maintenance of nuclear steam generators, a remote viewing capability is desirable. For example, there now exist means to provide surveillance within such steam generators while operations such as tube plugging, sleeving and cleaning are being performed. The devices which are presently used are heavy, bulky and require a relatively large amount of space in which to operate. As a result, such devices cannot be placed in certain areas of the steam generator where space is at a premium, such as near the tube sheet divider plate. This places a limitation on the effective viewing area of such devices, and thus, requires that they be repositioned often in order to fully view the area of interest. This is inconvenient, time consuming and expensive. Also, such devices may be jarred or dropped during repositioning, possibly resulting in damage.
Typically, presently available devices are mounted within the steam generator by means of a clamp specially designed for the particular pitch or spacing of the tubes in the steam generator. The clamp is sleeved into one or more steam generator tubes. Thus, different types steam generators require different clamps, which necessitates a greater inventory of customized parts and associated expense.
Presently available remote viewing devices are quite expensive and incorporate many different kinds of small parts. For example, many different sizes and shapes of fasteners are used to construct such devices. This means that a considerable inventory of various parts must necessarily be kept on hand and be readily available in the event that field repairs are necessary. Further, insasmuch as the devices contemplated herein are used in nuclear steam generators, it is expected that persons handling such equipment will be properly protected from radiation. In such situations, workers wear bulky protective clothing including multiple layers of gloves. Consequently, repair of currently available devices is quite difficult because the parts are small and difficult to handle. Thus, uniformity in the type and size of fasteners is desirable.
Field replacement of major components of presently available systems is also difficult and tedious work. For example, it is often very difficult to simply remove the lens from the camera or to remove the camera and lens from their supporting platform. Often a significant disassembly of component parts is necessary before major components may be interchanged. The difficulty of the various assembly and disassembly steps is further aggravated in a nuclear environment because of the requirement for workers to wear protective clothing.
Another problem associated with the use of any equipment in a nuclear environment is that the equipment sometimes becomes irradiated. Thus, bench repairs are often not practical. If the equipment fails, it is simply discarded and replaced at considerable cost.
Presently available systems typically use heavy and bulky cameras and remote controls. Often the weakest part of a camera is the so-called C-mount between the lens and the camera body. When jarred or dropped, the C-mount is usually the first part to break, causing irrepairable damage to the camera. Also, the lens may fall away and become damaged.
Remote viewing equipment of the type described usually includes means for adjusting the focus, zoom and aperture of the lens. These functions require separate controls which are normally built into the camera. These features, when incorporated into a camera, add considerably to its initial cost. Add-on equipment is available, but it is expensive and heavy. In either case, the cost and the weight of the equipment is considerable. Often, equipment useful for focusing or zooming the camera lens is specially designed by the manufacturer and is sometimes only compatible with cameras or lenses produced by that particular manufacturer. Thus, parts inventory is not uniform. The equipment useful for zoom, focus and aperture control employs mechanical stops and limiting devices which add to the weight cost and complexity of the equipment. Such devices, however, can be overdriven and the lens adjustment may be destroyed.